A number of diseases or injuries involving bones are known for which regeneration of bone is a desired treatment. Formation of bone in vivo involves an interaction of various inductive proteins and growth factors which act by causing a differentiation of mesenchymal cells into cartilage and then bone-forming cell lines. This mechanism is not completely understood. However, in efforts to improve orthopedic procedures, purified protein mixtures or recombinantly produced proteins have been developed which stimulate osteoinductive activity.
While such proteins have been shown to have osteoinductive activity, a difficulty in development of useful products is the identification of suitable delivery vehicles for the proteins. Among the first materials tested for delivery of bone growth proteins was hydroxyapatite. Bone growth protein and hydroxyapatite alone did not demonstrate increased bone formation. Addition of collagen to composites of these materials ameliorated the bone forming response, but the hydroxyapatite remained in the site and was not resorbed.
There exists a continuing need for the development of improved products and processes for the delivery of bone growth factors in treatment of orthopedic diseases and injuries.